The field of the invention is a process for synthesizing amorphous silica microspheres with fluorescence behavior and their applications.
U.S. Pat. No. 4,983,369 a process for producing highly uniform microspheres of silica having an average diameter of 0.1-10 microns from the hydrolysis of a silica precursor, such as tetraalkoxysilanes, which is characterized by employing precursor solutions and feed rates which initially yield a two-phase reaction mixture.
U.S. Pat. No. 4,943,425 teaches a method of making high purity, dense silica of large particles size. Tetraethylorthosilicate is mixed with ethanol and is added to a dilute acid solution having a pH of about 2.25. The resulting solution is digested for about 5 hours, then 2N ammonium hydroxide is added to form a gel at a pH of 8.5. The gel is screened through an 18-20 mesh screen, vacuum baked, calcined in an oxygen atmosphere and finally heated to about 1200 C. in air to form a large particle size, high purity, dense silica.
U.S. Pat. No. 4,965,091 teaches a sol-gel procedure is described for making display devices with luminescent films. The procedure typically involves hydrolysis and polymerization of an organometallic compound together with selected luminescent ions, and coating of a substrate and then heat treatment to form a polycrystalline layer.
U.S. Pat. No. 4,931,312 teaches luminescent thin films which are produced by a sol-gel process in which a gellable liquid is applied to a substrate to form a thin film, gelled and heated to remove volatile constituents and form a polycrystalline luminescent material.
U.S. Pat. No. 4,997,286 teaches an apparatus for measuring temperature in a region of high temperature which includes a sensor made from a fluorescent material, located within the region of high temperature. The fluorescent decay time of the fluorescent material is dependent upon the temperature of the fluorescent material.
U.S. Pat. No. 4,948,214 teaches an array of individual light emitters of a LED linear array each of which is imaged by a discrete step-index light guide and gradient index microlens device. The light guides consist of high refractive index cores, each surrounded by low refractive index matter. A multiplicity of light guides are deposited in channels formed in a host material, such as a silicon wafer. The host material between adjacent channels functions as an opaque separator to prevent cross-talk between adjacent light guides.
U.S. Pat. No. 4,925,275 teaches a liquid crystal color display which provides a transmitted light output that is of one or more colors, black, and/or white, as a function of the color of the incident light input and controlled energization or not of respective optically serially positioned liquid crystal color layers and/or multicolor composite liquid crystal color layer(s) in the display. In one case the display includes a plurality of liquid crystal color layers, each being dyed a different respective color, and apparatus for selectively applying a prescribed input, such as an electric field, to a respective layer or layers or to a portion or portions thereof. Each liquid crystal layer includes plural volumes of operationally nematic liquid crystal material in a containment medium that tends to distort the natural liquid crystal structure in the absence of a prescribed input, such as an electric field, and pleochroic dye is included or mixed with the liquid crystal material in each layer. Each layer is differently colored by the dye so as to have a particular coloring effect on light incident thereon. Exemplary layer colors may be yellow, cyan and magenta.
U.S. Pat. No. 4,957,349 teaches an active matrix screen for the color display of television images or pictures, control system which utilizes the electrically controlled birefringence effect and includes an assembly having a nematic liquid crystal layer with a positive optical anisotropy between an active matrix having transparent control electrodes and a transparent counter electrode equipped with colored filters and two polarizing means, which are complimentary of one another and are located on either side of the assembly.
U.S. Pat. No. 4,965,091 teaches a sol-gel procedure is described for making display devices with luminescent films. The procedure typically involves hydrolysis and polymerization of an organometallic compound together with selected luminescent ions, and coating of a substrate and then heat treatment to form a polycrystalline layer.
U.S. Pat. No. 4,948,843 teaches dye-containing polymers in which the dyes are organic in nature are incorporated into glasses produced by a sol-gel technique. The glasses may be inorganic or organic-modified metal oxide heteropolycondensates. The dye-containing polymers are covalently bonded to the glass through a linking group. The products of this invention can be used to make optically clear colored films which can be employed in the imaging, optical, solar heat energy and related arts.